Electronic equipment using semiconductor devices are essential for many modern applications. Three-dimensional (3D) stacked substrates are commonly involved in electronic equipment. The 3D stacked substrates include several stacked semiconductor die/chips/wafers that are physically and electrically interconnected with one another. Several die/chips/wafers are bonded and integrated through various interconnection structures. This allows higher component density in devices, such as mobile phones, digital cameras, etc.
Semiconductor image sensors are also commonly involved in electronic equipment. Complementary metal-oxide-semiconductor (CMOS) image sensors (CIS) are widely used in various applications, such as digital camera and mobile phone cameras. The CMOS image sensors are classified as front side illuminated (FSI) image sensors and back side illuminated (BSI) image sensors, depending on the light path difference. The BSI image sensors are gaining in popularity. The BSI image sensor includes an array of pixels. Each pixel includes a photo-diode, a transistor or a capacitor. Each pixel generates an electrical signal in response to incident light on the pixel. A magnitude of the electrical signal depends on the intensity of the incident light received by the respective pixels.
As technologies evolve, the semiconductor device is becoming increasingly smaller in size while having greater functionality and greater amounts of integrated circuitry. The manufacturing of the semiconductor device involves many complicated steps and operations. Since more different components with different materials are involved, complexity of the manufacturing and integration operations is increased. The increase in complexity of manufacturing may cause deficiencies such as delamination, cracking, high yield loss etc. The semiconductor device is produced in an undesired configuration, which would further exacerbate materials wastage and increase the manufacturing cost.
Therefore, there is a continuous need to modify structure and manufacturing method of the semiconductor device in order to improve the performance of the device as well as reduce cost and time on processing the device.